Underpinning



Oct. 26 1926. 1,604,277

J. E. GQLDSBOROUGH UNDERPI'NNING v Original Filed Oct. 3l, 1918 2 3 s. 4`Ii n Figo? Fig, Z

v IN VEN TOR Patented Cet. 26, 1926.

UNETED STATES JOHN GOLDSBOROUGH, OF BIEJOOKLYITg NEW YORK,

UNDERPINNING.

Original application iiied October 31, 1918. Serial No. 260,514. Dividedand this application filed October L5, 1925. Serial No. 62,670.

'.lhis invention relates to a method of .underpinning buildings andparticularly buildings that are supported upon isolated coluinns.

ln my copending application, Serial No. 260.7514, tiled October 31,1918, there is disclosed and claimed a method of underpinning a buildingwhich consists generally of producing excavations in the earth beneathand in alignment with the foundation of the building while leaving itSupported above each Xcavation by the natural arching action of thefoundation, and forming in the excavations sections of new foundationconsisting of piers and arches supported by and spanning the piers.

The present application, which is a division of my copending applicationreferred to above, relates to an embodiment of the inventionparticularly adapted for use when the building is supported .uponisolated columns. inasmuch as the function of underpinning is to lendadditional support to a structure by transferring its loadto a greaterdepth, the bearing area of its foundation must often be increased inorder to readily einplace the requisite underpinning means. In order toincrease the bearing area f a building sustained upon isolatedfoundation columns, a supplemental footing is used to join the footingsof the columns together in suoli a manner that the resultant structureis equivalent to a continuous foundation wall. W hen the supplementalfooting has been constructed between the' columns to embed theirfootings, spaced excavations are produced underneath t-hem which arefilled with foundation material, the natural arching action of thesupplementary footing being sufficient to temporarily support thefoundation until the underpinning operation has been completed.

The particular nature of the invention to which the specificationrelates as well as other objects and advantages thereof will appear'mostclearly from a description of the preferred embodiment shown in theaccompanying drawings in which like reference characters designate likeparts in the several views:

Figure 1 shows a foundation consisting of isolated piers;

Fig. 2 shows a supplemental footing binding the footings of the columnstogether;

Fig. 8 is a section of Fig. 2 along the line 3-3;

Fig. 4 shows the method of constructing the underpinning beneath thefootings; and

5 shows the completed underpinning.

Referring to the drawings, the building or other structure 1 issupported upon isolated columns, two of such columns being shown anddesignated 2 and 2 which are supported upon footings 4 and 5,respectively. The method 'can also be utilized to underpin a building ofthis character, and the first step, whereby the bearing area of thefoundation is increased, is shown in Fig. 2 where a keystone-shapedconcrete supplemental footing G is first placed in position to join thecolumn footings 4 and 5 together. rifhis suppleinental footing isconstructed by digging a trench around and between the column footings 4and 5 without disturbing the supporting earth beneath them. In doingthis, the column footings 4 and 5 are preferably undercut, as at 7 and8, so that when the concrete is cast into place the portion between tliecolumn footings 4 and 5 serves as a key of an arch whereby the columns 2and 3 are supported partially vertically and partially laterally by theconcrete supplemental footing block 6, which is shown in plan in Fig. 3.

The natural arching action of the footing thus constructed bearing onthe undisturbed earth beneath it is sufficient to support the buildingwhile the underpinning pier shafts aresunlr directly beneath the columnfootings 4 and 5, preferably in the improved manner disclosed in myPatent No. 1.143,184 for a method of lining an excavation and horizontalsheathing, dated June 15, 1915, or by any equivalent method of sheathingwhich will permit a shaft to be sunk in the L earth beneath a foundationwithout disturbing either the earthcontiguous to the shaft or thefoundation above it. Access to the space directly beneath the foundationis obtained by digging temporary lateral pits to a depth sufficient topermit ready excavating without otherwise disturbing the earthcontiguous to the foundation, which pits are subsequently filled up whenthe piers have been emplaced.

The method disclosed by the aforementioned patent and illustrated inFig. 4 consists in brief of sinking a shaft 9 in incre- Ll l)conditionsl and in this case the be, for example, approximately ,quvalentin area to the originalcolumns e loan of columns 2 and, 3 is sup'-by the arching action of the unitary footing consisting of the columnfootings -land and the supplemental footing G which bears on theremaining undisturbed earth. Experience has shown that such support issufi'icient to sustain theload without danger of settlement of any7portion of the foundation or building.V V

After the shafts have beenrsunk inthe manner described, they are filledwithfoundation matC-iiial,l preferably concrete, as shown in F ig. 4 toprovide a pier ll upon which the weight of column 3 is temporarilysustained by means of supports 12, which may be short I-beams as shown,or the like. The pier having been emplaced as shown at ll in Fig. ja',the haunch space between the end of supplemental footing 6, bottom ofcolumn footing` 5, and top of pier ll, and containing the I-beams 12, isthen filled with concrete to complete the arch shown in Fig. 5, andcomprising the key footing 6 interposed between hauiiches 13 and lllwhich rest upon piers 11l and 15V respectively `to complete that portionof the underpinning structure.

lWhile this lspecification and the. accompanying drawings disclose amethod of binding and underpinning .only two isolated foundationcolumns, it isv to be understood that any number of similarly adjacentcolumns may be likewise Iioiiied and underpinned, thatsthis,disclosurerelates merely to a preferred embodiment of the invention which has beenutilized for purposes of illustration, and that changes may be freelymade in the forni and method without departing from the spirit of theinvention withinthe scope of the appended claims.

l claim: i

l. A method of underpinning a building supported on isolated columns,which con- `sists ofbonding the footings of the columns with asupplemental footing` of foundation material, excavating shaftsbeneat-hthe colminis while leaving them temporarily supported by thenatural arching action of the Referat again to Fig. 4 it will be seensupplemental footing, and constructing supporting Apiers in saidexcavations.

rflic method of underpinning isolated co'lui'nn foundations whichconsists in bonding the footiiigs of the ycolumns with a supplementalfooting, sinking spaced shafts beneath the footings, and filling saidsl'iaft;l with foundation material to form piers Iwhereby the foundationload is transmitted to a greater depth.

3. The method of underpinning` a building simportedupon isolated columnswhich consists in yembedding the footings of a plurality of columns in asupplemental footing of foundation material, and coiistucting piersvunderneath the columns while toniporari-ly supporting the weight of thebuild -iiig upon the. supplemental footing.

di. The-method of underpinning` and bonding isolated foundation columnswhich convsistsnin 'embedding the bases lof, the columns in onefoot-ing, producing` excavation beneath and in alignment with thecolumns while leaving them supported by the arching actionojf thefooting above each excavation as it is produced, and forming piers inthe excavations.

5. The. method of underpinning a building supported `on columns whichconsists in jspanning the space between vthe footings of .the

columns with an arch-like beam, sinking shafts underneath the columns,the arch- .ing` action of the beam temporarily support- `ing the, columnload, and forming piers in the shafts to. complete the arch between the`column footings and to support the column load.'

6. The method of underpinning a column foundation which consists ofbonding the bases of the-columns in one footing, producinglspaceldexcavations beneath the footing and inalignment with the foundation,andconstructing piers in the excavations to.

support ,the fo'undation.

i 7. The method of underpinning a building supp'ortedby isolated columnswhich consiste `in undercutting the column footings, construct-ing asupplemental footing of foundation material. 'around and between thecol- JOHN B. GoLDsBonoUGH.

